Conventionally, in the lock stitch sewing machine, the serger, the double chain stitch sewing machine, or the cover stitch sewing machine, etc., it is well known that a cloth which should be sewed is sandwiched between a throat plate and a presser foot which is pressed by a presser bar and is fed stitch by stitch by a feed dog mechanism, and stitches are formed on the cloth by the sewing machine needle and a shuttle hook or a looper as a loop capturing device.
In the meantime, the shuttle hook or the looper as the loop capturing device and the feed dog mechanism are driven by each drive mechanism from a lower shaft which is a drive shaft. On the other hand, the sewing machine needle is screwed by a screw to the needle clamp which is attached to the needle bar which is driven with an upper shaft which is transferred from the lower shaft by a lower shaft pulley, a timing belt and an upper shaft pulley (cf: Patent document Nos. 1-4).